docs: bring the docs in line with the code and ship the font licences

[MotherSphere]

What changed and why

• Test counts removed. CONTRIBUTING.md (88), docs/architecture.md (131) and a ci.yml comment (140) each hard-coded a different number; the suite is at 150 today and keeps moving, so the counts are gone rather than updated.
• docs/colony-spec.md
  • The paragraph on the .meta sidecar said only the launcher's self-update consumes it, which contradicted the trust-boundary paragraph below it. The code (src/download.rs, the app install path) verifies app sidecars whenever they are published and pins them, so the earlier sentence was the wrong one.
  • "Since Colony 0.9.3": there is no 0.9.3 tag. The app-side sidecar check (feat: close the audit backlog - honest update checks, resumable installs, and a trust chain that reaches the apps #68) first ships in v0.10.0 (git grep save_installed_metadata v0.9.2 finds nothing, v0.10.0 has it).
  • The icon cache lives under <cache>/repo-icons/<repo>/icon.png (repo_icon_dir in src/persistence.rs), not <data>.
  • Dropped the claim that all Project-Colony apps have signed releases; not all of them do.
• README
  • colony-bin download is about 30 MB (v0.10.3 colony-linux is 30,299,936 bytes), not 40.
  • Stellar Blade palettes are marked fan-made and unofficial.
  • "For app developers" now says the catalogue only scans the Project-Colony organization (GITHUB_ACCOUNT in src/github/http.rs, /orgs/{GITHUB_ACCOUNT}/repos in src/github/catalog.rs).
  • License section mentions the bundled fonts and links each OFL text.
• 304s and the rate limit. GitHub only exempts a 304 from the primary rate limit when the request is authenticated. The comment on HTTP_CACHE in src/github/http.rs and docs/architecture.md said 304s are free outright. Comment and doc only, no behaviour change.
• Settings "About" card showed MotherSphere/Colony; the repository is Project-Colony/Colony.
• Font licences. Font Awesome Free 6.7.2 and OpenDyslexic shipped without their licence. Added OFL.txt next to each:
  • Font Awesome: copyright line and Reserved Font Name taken from the upstream 6.7.2 LICENSE.txt fonts section (the font's own name table only says "Copyright (c) Font Awesome"), followed by the standard OFL 1.1 text.
  • OpenDyslexic: the licence text embedded in the font's own name table (ID 13), copied verbatim.

Checks run locally (isolated XDG dirs)

• cargo fmt --all -- --check: pass
• cargo clippy --all-targets -- -D warnings: pass on the default toolchain and on rustc 1.99.0
• cargo test: 150 passed, 0 failed
• cargo check --locked --all-targets: pass

Not verified

• The MSRV leg was not run locally; the only code changes are a comment and a string literal.
• The settings screen was not opened to look at the new label.