fix: rebase fork deltas onto upstream v4.26.8

[Copilot]

Rebased the fork-specific master deltas onto upstream AstrBotDevs/AstrBot tag v4.26.8, while intentionally excluding the DingTalk patch already merged upstream (AstrBotDevs#9389). This keeps only the fork-maintained CI/docs additions and the MCP proxy behavior fix.

• Fork-only CI and maintenance docs

  • Added fork workflow: .github/workflows/docker-build.yml
  • Added fork maintenance guide: AGENTS.md

• MCP proxy behavior preserved after rebase

  • Updated _quick_test_mcp_connection in:
    • astrbot/core/agent/mcp_client.py
    • astrbot/core/provider/func_tool_manager.py
  • Session creation now honors environment proxy settings via trust_env=True.

# before
async with aiohttp.ClientSession() as session:

# after
async with aiohttp.ClientSession(trust_env=True) as session:

• Resulting delta vs v4.26.8 is intentionally limited to
  • .github/workflows/docker-build.yml
  • AGENTS.md
  • astrbot/core/agent/mcp_client.py
  • astrbot/core/provider/func_tool_manager.py

Original prompt

We need to rebase our fork's master branch onto the upstream tag v4.26.8 (AstrBotDevs/AstrBot).

Current state

Our master branch is based on v4.26.7 with 3 incremental commits on top:

1. fix: honor proxy settings for MCP connections — adds .github/workflows/docker-build.yml and changes aiohttp.ClientSession() to aiohttp.ClientSession(trust_env=True) in two files: astrbot/core/agent/mcp_client.py and astrbot/core/provider/func_tool_manager.py
2. fix(dingtalk): handle command errors and rich-text mentions — DingTalk fix that is NOW MERGED into upstream v4.26.8 (as fix(dingtalk): fix command parsing and error responses caused by rich text in the DingTalk HarmonyOS client. AstrBotDevs/AstrBot#9389), so this commit should be DROPPED during rebase
3. docs: document fork maintenance workflow — adds AGENTS.md

What to do

1. Add the upstream remote: git remote add upstream https://github.com/AstrBotDevs/AstrBot.git (it may already exist)

2. Fetch upstream tags: git fetch upstream --tags

3. Create a new branch rebase-v4.26.8 from the upstream tag v4.26.8 (commit 60c9e68d50dc9b9ed58503f21a0b77a8d0bd2159)

4. Apply our two incremental changes on top of v4.26.8:

   a. Copy .github/workflows/docker-build.yml from our current master branch (this is our custom CI workflow for building and publishing Docker images to GHCR)

   b. In astrbot/core/agent/mcp_client.py, find the _quick_test_mcp_connection function and change aiohttp.ClientSession() to aiohttp.ClientSession(trust_env=True) (there should be exactly one occurrence in this function)

   c. In astrbot/core/provider/func_tool_manager.py, find the _quick_test_mcp_connection function and change aiohttp.ClientSession() to aiohttp.ClientSession(trust_env=True) (there should be exactly one occurrence in this function)

   d. Copy AGENTS.md from our current master branch

5. Commit these changes with message: fix: honor proxy settings for MCP connections; add fork CI and docs

6. Push the rebase-v4.26.8 branch

7. Do NOT include the DingTalk fix commit — it's already in upstream v4.26.8.

Verification

After applying changes, verify that:

• git diff v4.26.8..HEAD --stat shows only these files changed: .github/workflows/docker-build.yml, astrbot/core/agent/mcp_client.py, astrbot/core/provider/func_tool_manager.py, AGENTS.md
• The aiohttp.ClientSession(trust_env=True) change is present in both Python files