feat: save and replay decoded sessions

[iPeluwa]

Summary

• I added a schema-versioned JSONL format that preserves decoded message timestamps, client addresses, direction, type, text, flat rendering, and rich RowDescription/DataRow details.
• I added --save FILE to continuously record the complete output stream before display filtering or TUI history eviction, while stdout or the TUI continues normally.
• I added --replay FILE as a file source that replaces pcap/mitm and feeds saved records through the existing stdout, display-filter, and rich TUI rendering pipeline.
• I added a TUI command bar on / and : with :save/:w and :open/:o commands.
• I documented schema version 1, replay behavior, compatibility rules, security considerations, CLI options, and TUI commands.

Design decisions

The saved format is structured JSONL rather than a plain transcript. Every record carries schema_version: 1 and an RFC 3339 timestamp. Message records retain the filter fields and optional rich-rendering payload, so replayed traffic behaves like live decoded traffic instead of becoming display-only text.

--save writes each completed JSONL line directly to disk before display filtering and independently of the bounded TUI history. Unknown schema versions, malformed records, invalid timestamps, and attempts to overwrite the replay input are refused with explicit errors.

CLI replay is instant and streams large files without retaining the full session. TUI open validates the complete file atomically and retains the newest 50,000 records. Opening from a live TUI switches the view to replay mode, closes any active recorder, and discards subsequent live display records so the two timelines cannot mix.

User impact

tapgres --save session.jsonl
tapgres --replay session.jsonl
tapgres --replay session.jsonl --tui --tui-rich
tapgres --replay session.jsonl -Y 'message.type == "Query"'

In the TUI, / or : opens the command bar:

:save session.jsonl
:open session.jsonl

Validation

• cargo fmt --all --check
• cargo test --all-targets (64 tests passed: 54 library, 5 protocol replay, 5 session CLI)
• cargo clippy --all-targets -- -D warnings
• cargo build --release
• generated manpage verification
• package-content verification for the schema documentation and compatibility fixture
• interactive rich-mode TUI replay and :open smoke test
• git diff --check

Closes #16.

[sunng87]

Can we confirm there is a new mode when we use tapgres --replay session.jsonl? tapgres should not be listening to pcap or tcp port for this mode, it's readonly.

[sunng87]

let me merge this first and verify by myself.