Introduce a versioned compact-placement lifecycle with v1 resume compatibility

[rosshd]

Parent: #58
Related: #56, #59, #61.

Problem

The current placement lifecycle is hard-coded to seven required stages in PLACEMENT_STAGES.
Persisted profiles store the current stage and evidence references against rubric coding-placement-v1.

The redesigned experience needs fewer, adaptive interactions, but changing the stage list in place would invalidate or misroute existing in-progress and provisional placements.

Goal

Introduce a versioned placement lifecycle contract that supports a compact interview sample while preserving exact recovery and interpretation of all v1 attempts.

This issue owns the state and compatibility foundation only.
The learner-facing compact conversation, editor restrictions, debrief, and result presentation are separate child issues.

Technical scope

• Define explicit lifecycle/rubric definitions instead of treating one global stage tuple as timeless.
• Add a compact v2 lifecycle with durable states for interview conversation, implementation, optional debrief, and completion.
• Bind each attempt to its lifecycle/rubric version at creation.
• Route stage progression, skip behavior, evidence bounds, result derivation, stale handling, and resume from the attempt's recorded version.
• Preserve append-only attempt evidence and immutable terminal attempts.
• Keep placement results provisional and separate from mastery.
• Ensure profile edits invalidate recommendations without deleting attempt history.
• Keep v1 profiles readable and resumable at their exact recorded stage.
• Reject malformed or unknown lifecycle versions safely.
• Do not silently reinterpret v1 evidence as v2 evidence.

Likely surfaces:

• src/openlearn/interview_prep.py
• src/openlearn/interview_attempts.py
• src/openlearn/cli.py
• tests/test_interview_prep.py
• tests/test_cli.py
• placement fixtures and schema documentation

Acceptance criteria

• New placements persist an explicit compact lifecycle and rubric version.
• A v1 in-progress placement resumes at the exact v1 stage and completes under v1 semantics.
• A v1 provisional result remains readable and is not recalculated under v2 rules.
• V2 stage progression supports an optional debrief without requiring placeholder evidence for skipped stages.
• /stop, /discard, /skip, and reduced-demand baseline behavior remain durable and idempotent.
• Runner, editor, or process interruption cannot become learner-failure evidence.
• Evidence references remain bounded by the lifecycle definition and survive restart without duplication.
• Placement completion grants no mastery and does not mark interview skills ready.
• Unknown or malformed lifecycle versions fail closed with a recoverable error.
• Unit tests cover new, v1 resume, v1 terminal, v2 interrupted, skipped, baseline, malformed, and repeated-sync cases.
• make check passes.

Out of scope

• User-facing interview dialogue and copy.
• Disabling editor autocomplete.
• Selecting the debrief question.
• Continuous recalibration from later practice.
• Full timed mock interviews.
• Data migration that rewrites historical attempt records.

[rosshd]

Implementation sequencing clarification:

• Introduce a versioned compact-placement lifecycle with v1 resume compatibility #68 introduces and tests the versioned lifecycle registry plus explicit v2 creation/progression APIs.
• The production CLI continues to start v1 placements until Replace placement questionnaires with a compact interviewer conversation #69 supplies the complete compact conversation and deliberately switches the default.
• Sync, status, validation, and resume in Introduce a versioned compact-placement lifecycle with v1 resume compatibility #68 must already dispatch from each persisted record's lifecycle version, so a future v2 record is safe.
• This avoids exposing a half-implemented v2 journey while keeping Replace placement questionnaires with a compact interviewer conversation #69 a consumer of a reviewed compatibility foundation.

Accordingly, the first acceptance item means placements explicitly created under the compact lifecycle persist v2. The default learner-facing switch belongs to #69.

[rosshd]

Board hygiene status: implementation is complete and validated on local main at 253743d, but that commit is not yet present on origin/main. Leaving this issue open until the local main branch is pushed; close it once the implementation is visible remotely.

[rosshd]

Implemented through the versioned placement lifecycle work beginning in 253743d and extended by the current reasoning-placement v3 contract. Legacy coding-placement v1/v2 records remain version-routed and resumable, malformed versions fail closed, terminal evidence remains immutable, and placement grants no mastery. Focused placement and journey tests passed on 76bf7b8.