feat: capture agent statistics via OTel and surface in safe outputs (#219)

* feat: add OTel JSONL parser for agent statistics

Create src/agent_stats.rs with AgentStats struct that parses Copilot
CLI OpenTelemetry file exporter output. Extracts model, token usage,
duration, tool calls, and turns from the last invoke_agent span and
execute_tool span counts.

Reuses ndjson::read_ndjson_file for JSONL parsing. Includes
to_markdown() renderer with collapsible details block.

9 unit tests including real copilot-otel.jsonl fixture.

Closes: part of #168

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* feat: plumb agent_name and agent_stats through ExecutionContext

- Add agent_name: Option<String> and agent_stats: Option<AgentStats>
  to ExecutionContext
- Plumb front_matter.name to ctx.agent_name in main.rs execute handler
- Load otel.jsonl from safe_output_dir, parse into ctx.agent_stats
  (non-fatal if missing — just logs debug/warn)
- Add OTel env vars to base.yml AWF step (always-on: COPILOT_OTEL_ENABLED,
  COPILOT_OTEL_FILE_EXPORTER_PATH, COPILOT_OTEL_EXPORTER_TYPE)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* feat: append agent stats to 6 safe output write actions

Append a collapsible markdown stats block to safe outputs that produce
human-readable content. Each tool reads include_stats from its typed
config struct (deserialized via ctx.get_tool_config), matching the
existing config pattern used for all other tool options.

Safe outputs with stats:
- create-pull-request (PR description)
- create-work-item (work item description)
- comment-on-work-item (comment body)
- add-pr-comment (PR comment body)
- create-wiki-page (wiki page content)
- update-wiki-page (wiki page content)

Per-tool opt-out via front matter:
  safe-outputs:
    create-pull-request:
      include-stats: false

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: sanitize OTel values, filter internal tools, remove redundant agent_name

Security:
- Sanitize model and agent_name before embedding in markdown stats
  block. Strips control chars, neutralizes ##vso[ pipeline commands,
  escapes pipe chars that break markdown tables. The OTel file is
  writable by the agent inside AWF, so these values are untrusted.

Bug fix:
- Filter out Copilot CLI internal tool spans (report_intent,
  permission) from tool_calls count. Only user-visible tool
  invocations are counted.

Cleanup:
- Remove redundant agent_name from ExecutionContext — AgentStats
  already stores it. Single source of truth.

Docs:
- Document include-stats option for all 6 safe outputs in AGENTS.md

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: replace <details> tags with plain markdown for ADO compatibility

Azure DevOps does not render HTML <details>/<summary> as collapsible
sections — they display as raw text. Switch to a horizontal rule +
italic heading + table, which renders correctly across ADO PRs, work
items, and wiki pages.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* refactor: compact single-line stats format, drop turns

Replace table with a single line using middle-dot separators:
🤖 _Agent Name_ · model · 45,230 in / 12,450 out · 23 tool calls · 4m 32s

Remove turns from output (low value to operators). Remove unused
total_tokens() method.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: Default impl bugs, dead internal tool filter, sanitization, PR footer order

Bugs fixed:
- CommentOnWorkItemConfig, CreateWikiPageConfig, UpdateWikiPageConfig:
  replace #[derive(Default)] with manual Default impls so include_stats
  defaults to true (not false from bool default)
- Remove dead "execute_tool permission" from INTERNAL_TOOL_NAMES — the
  real OTel span is "permission" (no prefix), already excluded by the
  starts_with("execute_tool") predicate

Improvements:
- Strip newlines in sanitize_for_markdown (single-line format)
- Reorder PR description: stats before provenance footer (footer is
  the final unambiguous security marker)
- Add trailing newlines to add_pr_comment.rs and create_work_item.rs

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: consolidate default_include_stats, plain agent name, doc comments, tests

- Remove italic underscores from agent name in stats line (plain text)
- Fix orphaned doc comment on compute_duration
- Consolidate 5 duplicate default_include_stats() fns into single
  pub(crate) fn in agent_stats.rs
- Add 3 unit tests for append_stats_to_body (opt-out, no-stats, with-stats)
- Fix trailing newlines

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jamesadevine

AGENTS.md

@@ -1022,6 +1022,7 @@ Adds a comment to an existing Azure DevOps work item. This is the ADO equivalent
 
 **Configuration options (front matter):**
 - `max` - Maximum number of comments per run (default: 1)
+- `include-stats` - Whether to append agent execution stats to the comment body (default: true)
 - `target` - **Required** — scoping policy for which work items can be commented on:
   - `"*"` - Any work item in the project (unrestricted, must be explicit)
   - `12345` - A specific work item ID
@@ -1053,6 +1054,7 @@ Creates an Azure DevOps work item.
 - `tags` - List of tags to apply
 - `custom-fields` - Map of custom field reference names to values (e.g., `Custom.MyField: "value"`)
 - `max` - Maximum number of create-work-item outputs allowed per run (default: 1)
+- `include-stats` - Whether to append agent execution stats to the work item description (default: true)
 - `artifact-link` - Configuration for GitHub Copilot artifact linking:
   - `enabled` - Whether to add an artifact link (default: false)
   - `repository` - Repository name override (defaults to BUILD_REPOSITORY_NAME)
@@ -1151,6 +1153,7 @@ Note: The source branch name is auto-generated from a sanitized version of the P
 - `labels` - List of labels to apply
 - `work-items` - List of work item IDs to link
 - `max` - Maximum number of create-pull-request outputs allowed per run (default: 1)
+- `include-stats` - Whether to append agent execution stats (token usage, duration, model) to the PR description (default: true)
 
 **Multi-repository support:**
 When `workspace: root` and multiple repositories are checked out, agents can create PRs for any allowed repository:
@@ -1204,6 +1207,7 @@ safe-outputs:
     comment-prefix: "[Agent Review] "  # Optional — prepended to all comments
     allowed-repositories: []           # Optional — restrict which repos can be commented on
     max: 1                             # Maximum per run (default: 1)
+    include-stats: true                # Append agent stats to comment (default: true)
 ```
 
 #### reply-to-pr-comment
@@ -1417,6 +1421,7 @@ safe-outputs:
     title-prefix: "[Agent] "        # Optional — prepended to the last path segment (the page title)
     comment: "Created by agent"     # Optional — default commit comment when agent omits one
     max: 1                          # Maximum number of create-wiki-page outputs allowed per run (default: 1)
+    include-stats: true             # Append agent stats to wiki page content (default: true)
 ```
 
 Note: `wiki-name` is required. If it is not set, execution fails with an explicit error message.
@@ -1442,6 +1447,7 @@ safe-outputs:
     title-prefix: "[Agent] "        # Optional — prepended to the last path segment (the page title)
     comment: "Updated by agent"     # Optional — default commit comment when agent omits one
     max: 1                          # Maximum number of update-wiki-page outputs allowed per run (default: 1)
+    include-stats: true             # Append agent stats to wiki page content (default: true)
 ```
 
 Note: `wiki-name` is required. If it is not set, execution fails with an explicit error message.