feat: validator, bundle builder and release checks for 0.1.0

- Add tools/validate.py: validates packages, and with --correction runs
  proposed corrections through the gate against a package without
  writing anything (spec/11 §11.4). The gate now refuses a proposal that
  fails the correction schema, rule correction.schema.
- tools/load.py validates every package before loading, and with
  --bundle --built-from builds a scienting-bundle/1 with the FTS5 search
  index and bundle_meta (spec/13 §13.5). Search rows are defined per
  unit (sentence, cell, equation outside a sentence, figure-text) with
  the parent kind as context.
- Roster keys carry a role, and a key with the role owner may revoke any
  receipt (spec/08 §8.7, spec/20); roster schema, store table and the
  fixture roster updated. The checker signs a trial revocation to prove
  the rule both ways.
- A qa: receipt raises the nodes it sampled except those in its errors
  (spec/08 §8.2); the example paper's fidelity counts become 27 F3,
  13 F2, 4 F1 and 1 F0.
- The destination chooses the keyed scheme, not the text policy:
  hmac-team between the team's machines, hkdf-pages outside the team
  (spec/05 §5.8, spec/12 §12.5).
- A TextQuoteSelector must repeat the anchor's plain quote and is absent
  for hashed or keyed anchors (spec/18 §18.3).
- Add fixtures/records/suspect.json, a scienting-suspect/1 record.
- Oracle: hashes are kept incrementally and checked after every
  correction against a full recomputation; load and write refuse unsafe
  manifest paths; Ed25519, HKDF and schema validation come from the
  cryptography and jsonschema packages; canonical JSON uses the built-in
  encoder with an exact RFC 8785 fallback.
- The tools need Python 3.14 with cryptography and jsonschema; the py310
  CI environment is dropped and the workflow runs the default only.
- Resolve every [CHECK] note in the docs, READMEs and context; add
  CONTRIBUTING.md; every tool answers --help and refuses unknown options.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/rationale.md

@@ -99,7 +99,7 @@ Only the three text values, `text_hash`, `match_hash` and `align_key`, normalize
 
 ### Hashes that leave the team are keyed
 
-A plain hash of "310.0" is recovered by hashing guesses, and overlapping anchors can rebuild passages [CHECK: the overlapping-anchors claim is the author's; spec/05 §5.8 gives only the guessing argument].
+A plain hash of "310.0" is recovered by hashing guesses, and overlapping anchors can rebuild passages.
 Inside a team, plain hashes are fine.
 
 An export to another machine of the team uses an HMAC (hash-based message authentication code), a hash that needs a secret key, under the team key.
@@ -124,7 +124,7 @@ Deciding whether a merged paragraph still holds "at least half" of what was anch
 
 ### Long quotations become a hash and a length
 
-Quotations over 200 code points are replaced by a hash and a length, which keeps anchors small and limits how much text an anchor carries [CHECK: reason for the cap is the author's; spec/06 §6.2 gives the number but not the reason].
+Quotations over 200 code points are replaced by a hash and a length, which keeps anchors small and limits how much text an anchor carries.
 A hashed window can still be found again in the node.
 
 ### Prefix and suffix pick between repeated quotes