feat: initial text-extract v0.1.0 (text.extract@0.1.0)

First real F∆I capability module. Ships as alpha in the store
index — installable, but layout-naive PDF extraction. Bumps to
1.0.0 require either the planned service-mode variant
(host-services-backed pdfium/mupdf) or confirmed-good
extraction quality on a representative document set.

Capability surface:

  Inputs:   document : bytes  (PDF or DOCX)
  Outputs:  extracted : json  (ExtractedDocument)
  Permissions: none — pure in-WASM, no filesystem, no network

Output schema:

  {
    "engine": "pdf-extract" | "zip+quick-xml",
    "engine_version": "<version>",
    "pages": [{ "number": <u32>, "text": <string>,
                "confidence?": <f64>, "bbox?": {x,y,w,h} }]
  }

The optional confidence and bbox fields are reserved for the
future service-mode variant. The host-services infrastructure
that backs pdfium/mupdf does not exist yet (Phase 0.5+); when
it lands, text-extract v0.2.0 will populate these fields without
an API break.

Engines:

  PDF:  pdf-extract 0.7 (pure Rust, MIT-licensed). Single-column
        documents extract reliably. Multi-column or table-heavy
        layouts may produce reordered text — documented in
        README as a known limitation of the in-WASM v0.1.0 path.

  DOCX: ad-hoc parser using the zip and quick-xml crates. Walks
        word/document.xml, concatenates run-level text, inserts a
        newline at each paragraph boundary. Tables, footnotes,
        and embedded objects are not extracted in v0.1.0.

The module is the first reference user of fai-module-sdk. The
public surface is one #[fai_module] function — no wit_bindgen,
no Guest impl, no allow attributes. Testing surface is the same
function via crate-type = ["cdylib", "rlib"]; the SDK macro
gates its WASM glue on target_arch = "wasm32" so host integration
tests work out of the box.

Tests: 6 unit + 3 integration, all green. The DOCX integration
test builds a minimal valid DOCX in memory and verifies the
JSON output schema. PDF integration coverage will land in a
follow-up once a representative test fixture is bundled.

The Forgejo CI workflow clones fai/module-sdk into a sibling
location to satisfy the path-based dev dependency. The path
will switch to a versioned git tag once SDK releases stabilize.

Signed-off-by: flemming-it <sf@flemming.it>

README.md

@@ -0,0 +1,85 @@
+# text-extract
+
+F∆I module — extract plain text from PDF and DOCX documents.
+
+## Capability
+
+| Field | Value |
+|-------|-------|
+| Capability | `text.extract@0.1.0` |
+| Inputs | `document: bytes` (PDF or DOCX) |
+| Outputs | `extracted: json` (ExtractedDocument) |
+| Permissions | _none_ — pure in-WASM, no filesystem, no network |
+| Status (in store index) | `alpha` |
+
+## Output schema
+
+```json
+{
+  "engine": "pdf-extract",
+  "engine_version": "0.7",
+  "pages": [
+    { "number": 1, "text": "..." }
+  ]
+}
+```
+
+`confidence` and `bbox` per page are reserved for a future
+service-mode variant (host-services-backed pdfium/mupdf engine).
+v0.1.0 does not populate them; the schema accepts them as
+optional so that v0.2.0 can extend without an interface break.
+
+## Build
+
+```bash
+cargo build --release --target wasm32-wasip2
+# Artifact: target/wasm32-wasip2/release/text_extract.wasm
+```
+
+The build depends on a sibling checkout of `fai/module-sdk`:
+
+```
+~/fai/
+├── module_sdk/                 # cloned from fai/module-sdk
+└── fai_modules/
+    └── text-extract/           # this repo
+```
+
+This is a temporary path-based dependency. Once `fai-module-sdk`
+is published to a registry or a stable git tag, this module's
+`Cargo.toml` will switch over. The Forgejo CI workflow checks out
+the SDK repo into a sibling directory before building.
+
+## Test
+
+```bash
+cargo test                       # 9 tests: 6 unit + 3 integration
+cargo test --release             # same, optimized
+```
+
+The DOCX path is covered end-to-end by an integration test that
+builds a minimal valid DOCX in memory and feeds it through
+`invoke`. The PDF path is covered by unit tests on the page
+splitter; full PDF coverage will land once the platform's hub
+loads this wasm component as part of its store-install
+integration test.
+
+## Limitations of v0.1.0
+
+- **Layout-naive PDF parsing.** Multi-column layouts and tables
+  may produce reordered text. Single-column documents work
+  reliably.
+- **DOCX text only.** Tables, footnotes, headers/footers and
+  embedded objects are not yet extracted. Plain paragraph text
+  with run-level concatenation is the v0.1.0 surface.
+- **No OCR.** Image-only PDFs return empty text per page.
+  An OCR variant will arrive as a separate module
+  (`text.ocr@x.y.z`) once the host-services infrastructure
+  for tesseract is in place.
+
+## License
+
+Apache-2.0. See `LICENSE`.
+
+Author: Dr. Stefan Flemming, Flemming.AI <platform@flemming.ai>
+Repository: https://git.flemming.ws/fai-modules/text-extract