Complete documentation rebuild

docs/internal/workspace.md

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+# Workspace internals
+
+## Purpose
+Define the local durable and run-local workspace model used by stages, manifests, resume, and archive.
+
+## Inputs and Outputs
+Inputs:
+- `pipeline.workspace.root`
+- `session.campaign`
+- `session.session_id`
+- generated `run_id`
+
+Outputs:
+- Session manifest at `{workspace.root}/work/{campaign}/{session_id}/manifest.json`
+- Run manifest at `{workspace.root}/work/{campaign}/{session_id}/runs/{run_id}/manifest.json`
+- Canonical durable session directories and run-local stage trees
+
+## Boundaries
+Owns:
+- Session-level path layout (`inputs/`, `audio/`, `transcripts/`, `artifacts/`, `reports/`, `logs/`, `config/`, `current/`, `runs/`)
+- Run-local stage sandbox layout under `runs/{run_id}/{stage}/`
+- Session lock acquisition/release (`.lock`)
+
+Does not own:
+- Stage business logic
+- Remote archive semantics (documented in `stage-archive.md`)
+- CLI argument parsing
+
+## Config Fields Used
+- `pipeline.workspace.root`
+- `pipeline.workspace.cleanup_after_archive`
+- `pipeline.spool.root`
+- `pipeline.spool.delete_audio_after_archive`
+- `session.campaign`
+- `session.session_id`
+
+## External Adapters Used
+None directly in this subsystem. Stages may use object storage adapters and then write local outputs into this layout.
+
+## State and Manifest Behavior
+- Session state is persisted in the session manifest (`manifest.Manifest`).
+- Invocation history is persisted per run in run manifests under `runs/{run_id}/manifest.json`.
+- During each run, stage outputs are often written run-local first (`runs/{run_id}/{stage}/outputs/...`) and promoted to canonical session paths after stage success.
+- `manifest.Artifacts` entries record `ProducerRunID` for durable outputs.
+- For S3 audio sessions, `prepare` records spool/work paths and S3 provenance in `manifest.Inputs`.
+
+## Skip and Resume Behavior
+- Skip/resume decisions are made in `internal/app` (`run_control.go`, `resume.go`) using stage status in the session manifest.
+- `--force` reruns selected stages and marks downstream previously-succeeded stages as `stale`.
+- Workspace layout is idempotent (`EnsureLayoutFor`) and reused across runs.
+
+## Failure Behavior
+- Failures preserve manifests and run-local files for inspection.
+- Lock conflicts fail fast via `ErrLockConflict`.
+- Cleanup can fail post-archive; failure is recorded in archive stage metadata and returned by the run.
+
+## Tests to Inspect Before Changing
+- `internal/artifacts/local_test.go`
+- `internal/stage/run_local_test.go`
+- `internal/app/run_control_test.go`
+- `internal/app/resume_run_stage_test.go`
+- `internal/app/post_archive_cleanup_test.go`
+
+## Architectural Invariants
+- Session root is campaign-aware: `{workspace.root}/work/{campaign}/{session_id}`.
+- Run roots are always nested: `runs/{run_id}` under the session root.
+- Run-local output promotion must end in canonical session paths.
+- Cleanup only targets run-scoped directories and must never delete configured root directories.