Implement ESRC-WP-0002/0003/0004: HTML/MD ingest, metadata, recovery

Add ingestHtml and ingestMarkdown with ADR-0003 pageless offset semantics,
PDF intrinsic metadata extraction with caller-wins merge (WP-0003), and
citation recovery primitives including re-ingest reconcile, local quote
search, and pluggable discovery hooks (ADR-0004). Mark all three workplans
finished with contract tests (80 passing).

workplans/ESRC-WP-0004-citation-recovery.md

@@ -4,14 +4,15 @@ type: workplan
 title: "Local citation recovery and external source discovery hooks"
 domain: infotech
 repo: evidence-source
-status: proposed
+status: finished
 owner: codex
 topic_slug: citation_evidence_mvp
 created: "2026-07-08"
-updated: "2026-07-08"
+updated: "2026-07-09"
 spec_refs:
   - INTENT.md
   - README.md
+  - docs/ADR-0004-citation-recovery-boundary.md
 state_hub_workstream_id: "2ce8b799-d67c-4dbf-aac5-0ff1f0363d62"
 ---
 
@@ -22,18 +23,17 @@ selector goes stale and discovering the external source a document was drawn
 from. This is the largest deferred strand and depends on the anchoring layer's
 selector model.
 
-## Open questions
+## Decisions (ADR-0004)
 
-- What is the recovery contract — does this repo *detect* stale selectors, or
-  only provide the re-ingest/re-fingerprint primitives the anchor layer calls?
-- Where does external source discovery (URL/DOI resolution) belong relative to
-  `citation-engine` and the umbrella?
+- `evidence-source` owns re-ingest/re-fingerprint, local quote search, and a
+  pluggable discovery hook registry (no network in core).
+- Stale selector detection and resolution order stay in `evidence-anchor`.
 
 ## Sketch
 
 ```task
 id: ESRC-WP-0004-T01
-status: todo
+status: done
 priority: low
 state_hub_task_id: "e7ff29b9-f04f-44f5-a23a-b028fc20a80b"
 ```
@@ -42,9 +42,9 @@ Design the recovery boundary with the anchor layer: define what
 
 ```task
 id: ESRC-WP-0004-T02
-status: todo
+status: done
 priority: low
 state_hub_task_id: "88a512d1-70e0-4bfa-b6b0-c1e4e31abb97"
 ```
 Prototype re-ingest/re-fingerprint recovery primitives and a discovery hook
-interface (no network coupling baked into the core).
+interface (no network coupling baked into the core).