feat: Prepare PKCS#11/TPM KEK support in storage

[gtema]

ADR 0016-v2 §2.1 named "HSM / PKCS#11 / Cloud KMS" as the production KEK
source but never specified a mechanism, leaving the Pkcs11KekStub as a
reserved-but-unimplemented interface boundary. Adds §2.5, specifying the
PKCS#11 (CKM_AES_GCM against a non-extractable token key, same wire
format as EnvKek) and TPM 2.0 (TPM-resident non-duplicable key,
Encrypt-then-MAC since TPM2 has no native AES-GCM command) KEK
mechanisms, plus invariants 13-15 covering non-extractable key material,
file-only credential input, and authenticate-before-decrypt for non-AEAD
providers.

Adds the corresponding kek_provider configuration schema
(crates/config/src/distributed_storage.rs): an env/pkcs11/tpm selector
with per-provider sections, cross-field validation (env requires
dev_mode, pkcs11/tpm require their config section, TPM key reference is
exactly one of handle or context file), and file-based secret loading
for the PKCS#11 PIN and TPM auth value, wired into Config::load_all
alongside the existing TLS cert loading.

This lands the ADR and config groundwork only; the storage-crypto-pkcs11
and storage-crypto-tpm provider crates, SoftHSM-backed integration test,
and TPM sample are follow-up work.

Tracks the sequencing for ADR 0016-v2 §2.5 (added in the previous
commit): crate layout, TPM trust model, and test/credential-input
decisions taken with the requester, plus the step-by-step plan from ADR
addendum + config schema (done) through provider crates, wiring, SoftHSM
CI test, docs, and supply-chain updates (not started). Kept out of
doc/src/SUMMARY.md since it's a working tracking doc, not user-facing
documentation.

Assisted-By: Claude Sonnet 5 noreply@anthropic.com
Signed-off-by: Artem Goncharov artem.goncharov@gmail.com

[github-actions]

🦢 Load Test Results

Goose Attack Report

Plan Overview

Action	Started	Stopped	Elapsed	Users
Increasing	26-07-03 11:15:40	26-07-03 11:15:58	00:00:18	0 → 30
Maintaining	26-07-03 11:15:58	26-07-03 11:16:28	00:00:30	30
Decreasing	26-07-03 11:16:28	26-07-03 11:16:28	00:00:00	0 ← 30

Request Metrics

Method	Name	# Requests	# Fails	Average (ms)	Min (ms)	Max (ms)	RPS	Failures/s
DELETE	DELETE /v3/auth/tokens	506	0	108.12	10	170	16.87	0.00
DELETE	DELETE /v3/projects/:id (teardown)	2	0	42.50	30	55	0.07	0.00
DELETE	DELETE /v3/users/:id (teardown)	3	0	43.33	31	52	0.10	0.00
GET		4618	0	101.81	73	200	153.93	0.00
GET	GET /v3/auth/tokens (validate new)	504	0	108.41	43	146	16.80	0.00
GET	GET /v3/projects/:id	723	0	82.94	72	110	24.10	0.00
GET	GET /v3/projects/:id (catalog)	718	0	83.17	72	120	23.93	0.00
GET	GET /v3/users/:id	1006	0	89.47	78	124	33.53	0.00
GET	GET /v3/users/:id (catalog)	791	0	89.09	80	119	26.37	0.00
POST	POST /v3/auth/tokens	502	0	81.64	72	111	16.73	0.00
	Aggregated	9373	0	96.11	10	200	312.43	0.00

Response Time Metrics

Method	Name	50%ile (ms)	60%ile (ms)	70%ile (ms)	80%ile (ms)	90%ile (ms)	95%ile (ms)	99%ile (ms)	100%ile (ms)
DELETE	DELETE /v3/auth/tokens	110	110	110	110	120	120	130	170
DELETE	DELETE /v3/projects/:id (teardown)	30	30	30	55	55	55	55	55
DELETE	DELETE /v3/users/:id (teardown)	47	47	47	47	52	52	52	52
GET		94	98	100	110	160	160	170	200
GET	GET /v3/auth/tokens (validate new)	110	110	110	110	120	120	130	146
GET	GET /v3/projects/:id	82	83	85	86	89	91	100	110
GET	GET /v3/projects/:id (catalog)	83	84	85	87	89	92	100	120
GET	GET /v3/users/:id	89	90	91	93	95	98	110	120
GET	GET /v3/users/:id (catalog)	88	89	90	92	95	97	110	119
POST	POST /v3/auth/tokens	81	82	83	85	87	89	99	110
	Aggregated	89	93	99	110	110	160	170	200

Status Code Metrics

Method	Name	Status Codes
DELETE	DELETE /v3/auth/tokens	506 [204]
DELETE	DELETE /v3/projects/:id (teardown)	2 [204]
DELETE	DELETE /v3/users/:id (teardown)	3 [204]
GET		4,618 [200]
GET	GET /v3/auth/tokens (validate new)	504 [200]
GET	GET /v3/projects/:id	723 [200]
GET	GET /v3/projects/:id (catalog)	718 [200]
GET	GET /v3/users/:id	1,006 [200]
GET	GET /v3/users/:id (catalog)	791 [200]
POST	POST /v3/auth/tokens	502 [200]
	Aggregated	8,862 [200], 511 [204]

Transaction Metrics

Transaction	# Times Run	# Fails	Average (ms)	Min (ms)	Max (ms)	RPS	Failures/s
ReadHeavy
0.0	1	0	27.00	27	27	0.03	0.00
0.1	784	0	101.17	89	136	26.13	0.00
0.2	784	0	84.10	74	112	26.13	0.00
0.3	782	0	82.95	73	111	26.07	0.00
TokenLifecycle
1.0	0	0	0.00	0	0	0.00	0.00
1.1	506	0	299.26	135	348	16.87	0.00
ValidateToken
2.0	0	0	0.00	0	0	0.00	0.00
2.1	761	0	158.05	144	200	25.37	0.00
UserCRUD
3.0	0	0	0.00	0	0	0.00	0.00
3.1	0	0	0.00	0	0	0.00	0.00
3.2	1006	0	89.52	78	124	33.53	0.00
3.3	3	0	43.33	31	52	0.10	0.00
ProjectCRUD
4.0	0	0	0.00	0	0	0.00	0.00
4.1	0	0	0.00	0	0	0.00	0.00
4.2	723	0	82.99	72	111	24.10	0.00
4.3	2	0	42.50	30	55	0.07	0.00
UserRead
5.0	0	0	0.00	0	0	0.00	0.00
5.1	791	0	100.62	81	132	26.37	0.00
5.2	791	0	89.15	80	120	26.37	0.00
ProjectRead
6.0	0	0	0.00	0	0	0.00	0.00
6.1	716	0	84.28	74	111	23.87	0.00
6.2	718	0	83.21	72	120	23.93	0.00
Aggregated	8368	0	107.65	27	348	278.93	0.00

Scenario Metrics

Transaction	# Users	# Times Run	Average (ms)	Min (ms)	Max (ms)	Scenarios/s	Iterations
ReadHeavy	7	781	269.22	250	315	26.03	111.57
TokenLifecycle	5	501	299.71	278	348	16.70	100.20
ValidateToken	4	757	158.03	144	200	25.23	189.25
UserCRUD	3	1003	89.50	78	124	33.43	334.33
ProjectCRUD	2	721	82.99	72	111	24.03	360.50
UserRead	5	790	190.26	175	233	26.33	158.00
ProjectRead	4	715	167.96	155	204	23.83	178.75
Aggregated	30	5268	170.85	72	348	175.60	1432.60

View full report

[github-actions]

Bencher Report

Branch	claude/raft-pkcs11-tpm-support-tc29i2
Testbed	ubuntu-latest

Click to view all benchmark results

Benchmark	Latency	Benchmark Result nanoseconds (ns) (Result Δ%)	Upper Boundary nanoseconds (ns) (Limit %)
Command_Serde/apply/remove	📈 view plot 🚷 view threshold	130,570.00 ns (-56.46%) Baseline: 299,875.94 ns	1,712,790.26 ns (7.62%)
Command_Serde/apply/set	📈 view plot 🚷 view threshold	142,090.00 ns (-43.64%) Baseline: 252,112.19 ns	1,028,781.94 ns (13.81%)
Command_Serde/pack/delete	📈 view plot 🚷 view threshold	127.73 ns (+5.45%) Baseline: 121.13 ns	145.36 ns (87.87%)
Command_Serde/pack/delete_index	📈 view plot 🚷 view threshold	111.72 ns (+1.67%) Baseline: 109.89 ns	131.44 ns (85.00%)
Command_Serde/pack/set	📈 view plot 🚷 view threshold	219.26 ns (+12.72%) Baseline: 194.52 ns	236.54 ns (92.70%)
Command_Serde/pack/set_index	📈 view plot 🚷 view threshold	111.55 ns (+1.68%) Baseline: 109.71 ns	130.88 ns (85.23%)
Command_Serde/unpack/delete	📈 view plot 🚷 view threshold	193.18 ns (+0.30%) Baseline: 192.59 ns	235.33 ns (82.09%)
Command_Serde/unpack/delete_index	📈 view plot 🚷 view threshold	170.70 ns (+6.73%) Baseline: 159.93 ns	198.56 ns (85.97%)
Command_Serde/unpack/set	📈 view plot 🚷 view threshold	294.37 ns (+10.56%) Baseline: 266.24 ns	331.53 ns (88.79%)
Command_Serde/unpack/set_index	📈 view plot 🚷 view threshold	166.83 ns (+4.76%) Baseline: 159.25 ns	196.77 ns (84.78%)
Payload_encryption/pack/remove_cmd	📈 view plot 🚷 view threshold	122.54 ns (+5.99%) Baseline: 115.62 ns	139.80 ns (87.65%)
Payload_encryption/pack/set_cmd	📈 view plot 🚷 view threshold	217.04 ns (+7.55%) Baseline: 201.81 ns	266.25 ns (81.52%)
Payload_encryption/unpack/remove_cmd	📈 view plot 🚷 view threshold	213.07 ns (+4.15%) Baseline: 204.57 ns	253.19 ns (84.15%)
Payload_encryption/unpack/set_cmd	📈 view plot 🚷 view threshold	304.11 ns (+9.01%) Baseline: 278.96 ns	349.98 ns (86.89%)
Raft_1Node_Latency/prefix/1node	📈 view plot 🚷 view threshold	2,572,900.00 ns (-7.15%) Baseline: 2,771,084.22 ns	6,322,932.89 ns (40.69%)
Raft_1Node_Latency/read/1node	📈 view plot 🚷 view threshold	43,431.00 ns (+153.32%) Baseline: 17,144.78 ns	64,689.22 ns (67.14%)
Raft_1Node_Latency/remove/1node	📈 view plot 🚷 view threshold	389,760.00 ns (-31.61%) Baseline: 569,913.59 ns	2,316,710.74 ns (16.82%)
Raft_1Node_Latency/write/1node	📈 view plot 🚷 view threshold	407,570.00 ns (-31.22%) Baseline: 592,592.03 ns	2,149,088.86 ns (18.96%)
build_snapshot/default	📈 view plot 🚷 view threshold	120,530.00 ns (+10.34%) Baseline: 109,230.97 ns	162,891.27 ns (73.99%)
fernet token/project	📈 view plot 🚷 view threshold	1,418.90 ns (+2.82%) Baseline: 1,379.92 ns	1,634.83 ns (86.79%)
get_data_keyspace	📈 view plot 🚷 view threshold	0.31 ns (-0.68%) Baseline: 0.31 ns	0.37 ns (85.10%)
get_db	📈 view plot 🚷 view threshold	0.31 ns (-0.40%) Baseline: 0.31 ns	0.37 ns (85.41%)
get_fernet_token_timestamp/project	📈 view plot 🚷 view threshold	155.25 ns (+8.61%) Baseline: 142.95 ns	178.90 ns (86.78%)
get_keyspace	📈 view plot 🚷 view threshold	4.43 ns (-8.24%) Baseline: 4.83 ns	9.76 ns (45.43%)

🐰 View full continuous benchmarking report in Bencher