chore(release): beta packaging — signing, changelog, store metadata, scale test

- Android release signing reads a gitignored key.properties, falling back
  to debug keys so contributors can still build --release.
- CHANGELOG.md (human, newest-first) + Fastlane/F-Droid metadata (en/es)
  with descriptions derived from docs/intro.md.
- docs/release.md: the by-hand build + manual smoke checklist (no CI yet).
- inventory_scale_test guards the list query against N+1 at 3000 varieties.

CHANGELOG.md

@@ -0,0 +1,32 @@
+# Changelog
+
+All notable changes to Tanemaki are recorded here. Human-readable, newest
+first. Dates are ISO (YYYY-MM-DD).
+
+## [Unreleased] — Block 1 beta prep
+
+Block 1 is the offline, encrypted seed inventory — useful with zero network.
+
+### Added
+- **Local sharing.** Mark a batch as to give away, to swap or for sale (gift
+  and swap first, sale never the default). A "what I share" filter and a
+  printable catalog (a paper bridge for fairs) surface it.
+- **Sealed backups & recovery.** "Save a backup" writes a single encrypted
+  file; restoring on your own device is silent, and a copy from another
+  identity opens with the printed recovery code — which also brings your
+  identity back. A printable recovery sheet (QR + code) lives in Settings.
+- **Full editing.** Lots and vernacular names can be edited and removed, not
+  just added.
+- **Portuguese** interface, alongside Spanish and English; right-to-left
+  layouts verified.
+
+### Changed
+- "How much I have" is answered by the coarse abundance scale (plenty to
+  share … running low), which now nudges toward sharing when you have plenty.
+  A precise gram/seed-count field is deferred until network offers need it.
+
+### Notes
+- Everything is local-first and encrypted at rest (SQLCipher). No account, no
+  server, no tracking.
+- The social layer (network offers, messaging, web of trust) is Block 2 and
+  intentionally not part of this release.