Rebuild extraction pipeline infrastructure (Faza 0 prep)

Implements the approved plan to replace the broken regex/index-master
extraction with an LLM-subagent pipeline. Four parallel lanes:

Lane A — scripts/extract_common.py (PDF/docx/doc/pptx/html/zip, no
  max_pages truncation), normalize_sources.py, chunk_sources.py
  (~20pg chunks + overlap, manifest registry), activity_schema.json.
Lane B — app/config_taxonomy.py (16 fixed category slugs), schema
  rebuilt from scratch in app/models/ with content_type, language,
  source_files, source_excerpt, normalized_name, extraction_confidence,
  needs_review; FTS5 + 3 triggers extended with materials_list and
  skills_developed.
Lane C — build_database.py (--rebuild, atomic swap, schema + fuzzy
  source_excerpt validation, dedup with needs_review band),
  validate_extractions.py, review_queue.py, new run_extraction.py
  orchestrator, SUBAGENT_PROMPT.md.
Lane D — search.py content_type/language filters (default search
  excludes non-game content), E7 schema-compat audit; fixed a NULL
  keywords AttributeError in _boost_search_relevance.

Removes 8 orphaned/dead scripts and app/services/parser.py +
indexer.py. Adds tests/ (70 passing, 1 skipped — libreoffice absent).

Note: Lane D made one additive edit to app/models/database.py
(_update_category_counts) to surface content_type/language in
get_filter_options, outside its nominal lane boundary but after
Lane B completed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/SUBAGENT_PROMPT.md

@@ -0,0 +1,81 @@
+# SUBAGENT — Activity extraction
+
+You are a subagent in the game-library extraction pipeline. You extract
+educational activities (games, team-building, scouting, recipes, songs,
+ceremonies) from one chunk of a source document into structured JSON.
+
+## Your task
+
+1. **Read ONLY the chunk you were assigned.** Do not read other chunks, other
+   files, or the original document. The chunk is a `.txt` file with
+   `--- PAGE N ---` markers.
+2. Identify **every distinct activity** in the chunk.
+3. For each activity, fill the schema in `scripts/activity_schema.json`.
+4. Write the result to `data/extracted/<chunk_key>.json`.
+
+## What counts as "a distinct activity"
+
+A distinct activity is a self-contained game/activity/recipe/song/ceremony with
+its own name and a real description of how to do it. It is NOT:
+
+- a bare mention or a cross-reference with no description — **skip it**;
+- a sub-variant of an activity already extracted — fold it into `variations`;
+- a heading, a table of contents entry, or running page chrome.
+
+If the same activity is split across a page boundary inside your chunk, treat it
+as **one** activity and combine the text.
+
+## Output format
+
+The file is one JSON object: a `header` plus an `activities` array.
+
+```json
+{
+  "header": {
+    "source_id": "<set from the prompt>",
+    "chunk_key": "<set from the prompt>",
+    "source_hash": "<set from the prompt>",
+    "schema_version": "1.0",
+    "prompt_version": "1.0",
+    "chunk_range": "pages 1-20"
+  },
+  "activities": [ ... ]
+}
+```
+
+## Rules for each activity
+
+- **`name`** — the activity's real name (≥3 characters).
+- **`description`** — real prose describing the activity. No hard length limit,
+  but it must actually describe what happens.
+- **`rules`** — how it is played / carried out, if the source gives rules.
+- **`category`** — exactly one taxonomy slug (see the `enum` in the schema):
+  `jocuri-cercetasesti`, `team-building`, `icebreakers`, `camp-outdoor`,
+  `wide-games`, `orientare`, `prim-ajutor`, `escape-room-puzzle`,
+  `creative-stem`, `sports-active`, `cantece-ceremonii`, `retete`,
+  `supravietuire`, `integrare-incluziune`, `conflict-empatie`, `altele`.
+  When unsure, use `altele`.
+- **`content_type`** — the FORM of the content, independent of category:
+  `joc`, `activitate`, `reteta`, `cantec`, or `ceremonie`.
+- **`language`** — `ro` or `en` (the language the activity is written in).
+- **`source_excerpt`** — **MANDATORY.** A short quote (one or two sentences)
+  copied **verbatim** from the chunk. This is the anti-hallucination anchor: it
+  is checked as a fuzzy substring of the chunk, and invented quotes are
+  rejected.
+- **`page_reference`** — **MANDATORY.** The `--- PAGE N ---` marker(s) the
+  activity came from, e.g. `"page 14"` or `"pages 14-15"`.
+- **`extraction_confidence`** — `high`, `med`, or `low`. Use `low` when the
+  source text for the activity is thin or ambiguous.
+
+## Never invent data
+
+- Do **not** invent ages, participant counts, or durations. If the source does
+  not state them, leave those fields `null`.
+- Do **not** paraphrase the `source_excerpt` — copy it character for character.
+- Better to extract fewer activities accurately than to pad the output.
+
+## Before you finish
+
+- Every activity has a non-empty `source_excerpt` and `page_reference`.
+- The file validates against `scripts/activity_schema.json`.
+- You only used text from your assigned chunk.