ACP: add persistent Discord channel and Telegram topic bindings (#34873)

* docs: add ACP persistent binding experiment plan

* docs: align ACP persistent binding spec to channel-local config

* docs: scope Telegram ACP bindings to forum topics only

* docs: lock bound /new and /reset behavior to in-place ACP reset

* ACP: add persistent discord/telegram conversation bindings

* ACP: fix persistent binding reuse and discord thread parent context

* docs: document channel-specific persistent ACP bindings

* ACP: split persistent bindings and share conversation id helpers

* ACP: defer configured binding init until preflight passes

* ACP: fix discord thread parent fallback and explicit disable inheritance

* ACP: keep bound /new and /reset in-place

* ACP: honor configured bindings in native command flows

* ACP: avoid configured fallback after runtime bind failure

* docs: refine ACP bindings experiment config examples

* acp: cut over to typed top-level persistent bindings

* ACP bindings: harden reset recovery and native command auth

* Docs: add ACP bound command auth proposal

* Tests: normalize i18n registry zh-CN assertion encoding

* ACP bindings: address review findings for reset and fallback routing

* ACP reset: gate hooks on success and preserve /new arguments

* ACP bindings: fix auth and binding-priority review findings

* Telegram ACP: gate ensure on auth and accepted messages

* ACP bindings: fix session-key precedence and unavailable handling

* ACP reset/native commands: honor fallback targets and abort on bootstrap failure

* Config schema: validate ACP binding channel and Telegram topic IDs

* Discord ACP: apply configured DM bindings to native commands

* ACP reset tails: dispatch through ACP after command handling

* ACP tails/native reset auth: fix target dispatch and restore full auth

* ACP reset detection: fallback to active ACP keys for DM contexts

* Tests: type runTurn mock input in ACP dispatch test

* ACP: dedup binding route bootstrap and reset target resolution

* reply: align ACP reset hooks with bound session key

* docs: replace personal discord ids with placeholders

* fix: add changelog entry for ACP persistent bindings (#34873) (thanks @dutifulbob)

---------

Co-authored-by: Onur <2453968+osolmaz@users.noreply.github.com>

docs/experiments/proposals/acp-bound-command-auth.md

@@ -0,0 +1,89 @@
+---
+summary: "Proposal: long-term command authorization model for ACP-bound conversations"
+read_when:
+  - Designing native command auth behavior in Telegram/Discord ACP-bound channels/topics
+title: "ACP Bound Command Authorization (Proposal)"
+---
+
+# ACP Bound Command Authorization (Proposal)
+
+Status: Proposed, **not implemented yet**.
+
+This document describes a long-term authorization model for native commands in
+ACP-bound conversations. It is an experiments proposal and does not replace
+current production behavior.
+
+For implemented behavior, read source and tests in:
+
+- `src/telegram/bot-native-commands.ts`
+- `src/discord/monitor/native-command.ts`
+- `src/auto-reply/reply/commands-core.ts`
+
+## Problem
+
+Today we have command-specific checks (for example `/new` and `/reset`) that
+need to work inside ACP-bound channels/topics even when allowlists are empty.
+This solves immediate UX pain, but command-name-based exceptions do not scale.
+
+## Long-term shape
+
+Move command authorization from ad-hoc handler logic to command metadata plus a
+shared policy evaluator.
+
+### 1) Add auth policy metadata to command definitions
+
+Each command definition should declare an auth policy. Example shape:
+
+```ts
+type CommandAuthPolicy =
+  | { mode: "owner_or_allowlist" } // default, current strict behavior
+  | { mode: "bound_acp_or_owner_or_allowlist" } // allow in explicitly bound ACP conversations
+  | { mode: "owner_only" };
+```
+
+`/new` and `/reset` would use `bound_acp_or_owner_or_allowlist`.
+Most other commands would remain `owner_or_allowlist`.
+
+### 2) Share one evaluator across channels
+
+Introduce one helper that evaluates command auth using:
+
+- command policy metadata
+- sender authorization state
+- resolved conversation binding state
+
+Both Telegram and Discord native handlers should call the same helper to avoid
+behavior drift.
+
+### 3) Use binding-match as the bypass boundary
+
+When policy allows bound ACP bypass, authorize only if a configured binding
+match was resolved for the current conversation (not just because current
+session key looks ACP-like).
+
+This keeps the boundary explicit and minimizes accidental widening.
+
+## Why this is better
+
+- Scales to future commands without adding more command-name conditionals.
+- Keeps behavior consistent across channels.
+- Preserves current security model by requiring explicit binding match.
+- Keeps allowlists optional hardening instead of a universal requirement.
+
+## Rollout plan (future)
+
+1. Add command auth policy field to command registry types and command data.
+2. Implement shared evaluator and migrate Telegram + Discord native handlers.
+3. Move `/new` and `/reset` to metadata-driven policy.
+4. Add tests per policy mode and channel surface.
+
+## Non-goals
+
+- This proposal does not change ACP session lifecycle behavior.
+- This proposal does not require allowlists for all ACP-bound commands.
+- This proposal does not change existing route binding semantics.
+
+## Note
+
+This proposal is intentionally additive and does not delete or replace existing
+experiments documents.