docs: bring pending doc updates onto main

[ysyneu]

Brings the still-relevant content of several open docs PRs onto current main. Each of those PRs conflicted with main, so the content was re-applied hunk by hunk against the current pages instead of rebasing. Every added fact was checked against the product source on its default branch. Claims that could not be confirmed were left out.

PR	Outcome
#1045	Ported: CLI --fields, the FLASHDUTY_CONSOLE_URL reserved variable, MCP/Skill list entry points, AI SRE as a work-item assignee, RUM Issue auto-analysis, dashboard panel refresh, and IM attachments plus the topic-session lookback. Left out: refresh queue-jumping and the DingTalk reaction table (not confirmable).
#1057	Ported: console page actions in sessions, the AI noise-analysis entry, service-calendar behaviors, investigation-entry defaults, the folder move dialog, dashboard search, remembered page sizes, CLI/SDK calendar and work-item commands, and the RUM 50-application cap. Left out: queue withdrawal and rule-move permission claims.
#1062	Ported: automation execution place (run_in, chat_scope_mismatch), RUM resolve modes, DingTalk/Feishu member auto-linking and Slack linking, literal wildcards in filters and routing rules, CLI monit folder-* / --run-in, and Go SDK RuleFolders / Automations. Left out: the stored-value rewrite note and the concurrent-run skip claim.
#1026	Ported only the device_type:Mobile example fix. The Ask AI rewrite does not match the shipped RUM explorer, which still uses the preview-and-apply flow.
#1051	Ported as an "if an APP key is exposed" section in the OpenAPI introduction: create a replacement, switch integrations, then disable or delete the old key.
#1061	Nothing to port: resolve_mode and the automation execution-location fields are already on main with more accurate wording.
#1025	Nothing to port: the session-list incident_id filter is not in the released API, and ref is already documented.

Also adds changelog entries for 10-12, 10-15 and 10-16.

Checks: mint broken-links and mint validate pass, scripts/api_path_redirects.py --check and scripts/lint_openapi.py pass, and the integration-docs build/check passes (348 keys).