refactor: switch the whole project to English

talk is going to be published. Code comments, CLI output, error messages,
daemon log lines, MCP descriptions and results, test names and assertions,
README, spec, skill, build scripts and flake are now English. Only the
spoken announcement texts stay bilingual: the wrap result and the test
sentence are German or English depending on the detected language.

Language fallback is now configurable: `lang = "en" | "de"` (env
TALK_LANG, default en) is used when detection cannot tell (numbers, single
words, ties) and for talk's own announcements. langdetect.Detect takes the
fallback as an argument instead of hard-coding German. `talk setup` asks for
it; `talk doctor` and `talk status` show it.

Vocabulary pinned across packages so the process-boundary tests observe
stable strings: chain log lines ("chain: tier X skipped (not available)",
"falling back to the next tier", "spoken via X"), queue lines ("discarded:
quiet hours ... active", "replaced by toast", "max_age"), CLI notes
("speaking directly", "daemon started at", "no daemon", "nothing to cancel"),
status block with aligned English labels, MCP messages, origin guard 403.

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

scripts/release.sh

@@ -1,14 +1,14 @@
 #!/usr/bin/env sh
-# Baut die Release-Artefakte von talk für alle Zielplattformen — reproduzierbar
-# mit nichts als dem Go-Toolchain (kein GoReleaser nötig; so läuft derselbe
-# Schritt lokal, in Gitea Actions und in nix identisch).
+# Builds the talk release artifacts for all target platforms, reproducibly
+# with nothing but the Go toolchain (no GoReleaser needed; this way the same
+# step runs identically locally, in Gitea Actions and in nix).
 #
-# Asset-Vertrag (agent-lib-Muster, Fleet-Rollout pinnt darauf):
-#   dist/talk_<os>_<arch>[.exe]   statisches Binary, CGO_ENABLED=0
-#   dist/checksums.txt            sha256 je Asset (sha256sum-Format)
+# Asset contract (agent-lib pattern, the fleet rollout pins to it):
+#   dist/talk_<os>_<arch>[.exe]   static binary, CGO_ENABLED=0
+#   dist/checksums.txt            sha256 per asset (sha256sum format)
 #
-# Aufruf:  scripts/release.sh [VERSION]      (Default: git describe, sonst "dev")
-# Env:     TARGETS="linux/amd64 …" überschreibt die Matrix.
+# Usage:  scripts/release.sh [VERSION]      (default: git describe, else "dev")
+# Env:    TARGETS="linux/amd64 ..." overrides the matrix.
 set -eu
 
 cd "$(dirname "$0")/.."