feat: add PDF analysis tool with native provider support (#31319)

* feat: add PDF analysis tool with native provider support

New `pdf` tool for analyzing PDF documents with model-powered analysis.

Architecture:
- Native PDF path: sends raw PDF bytes directly to providers that support
  inline document input (Anthropic via DocumentBlockParam, Google Gemini
  via inlineData with application/pdf MIME type)
- Extraction fallback: for providers without native PDF support, extracts
  text via pdfjs-dist and rasterizes pages to images via @napi-rs/canvas,
  then sends through the standard vision/text completion path

Key features:
- Single PDF (`pdf` param) or multiple PDFs (`pdfs` array, up to 10)
- Page range selection (`pages` param, e.g. "1-5", "1,3,7-9")
- Model override (`model` param) and file size limits (`maxBytesMb`)
- Auto-detects provider capability and falls back gracefully
- Same security patterns as image tool (SSRF guards, sandbox support,
  local path roots, workspace-only policy)

Config (agents.defaults):
- pdfModel: primary/fallbacks (defaults to imageModel, then session model)
- pdfMaxBytesMb: max PDF file size (default: 10)
- pdfMaxPages: max pages to process (default: 20)

Model catalog:
- Extended ModelInputType to include "document" alongside "text"/"image"
- Added modelSupportsDocument() capability check

Files:
- src/agents/tools/pdf-tool.ts - main tool factory
- src/agents/tools/pdf-tool.helpers.ts - helpers (page range, config, etc.)
- src/agents/tools/pdf-native-providers.ts - direct API calls for Anthropic/Google
- src/agents/tools/pdf-tool.test.ts - 43 tests covering all paths
- Modified: model-catalog.ts, openclaw-tools.ts, config schema/types/labels/help

* fix: prepare pdf tool for merge (#31319) (thanks @tyler6204)

docs/gateway/configuration-reference.md

@@ -835,6 +835,12 @@ Time format in system prompt. Default: `auto` (OS preference).
         primary: "openrouter/qwen/qwen-2.5-vl-72b-instruct:free",
         fallbacks: ["openrouter/google/gemini-2.0-flash-vision:free"],
       },
+      pdfModel: {
+        primary: "anthropic/claude-opus-4-6",
+        fallbacks: ["openai/gpt-5-mini"],
+      },
+      pdfMaxBytesMb: 10,
+      pdfMaxPages: 20,
       thinkingDefault: "low",
       verboseDefault: "off",
       elevatedDefault: "on",
@@ -853,6 +859,11 @@ Time format in system prompt. Default: `auto` (OS preference).
 - `imageModel`: accepts either a string (`"provider/model"`) or an object (`{ primary, fallbacks }`).
   - Used by the `image` tool path as its vision-model config.
   - Also used as fallback routing when the selected/default model cannot accept image input.
+- `pdfModel`: accepts either a string (`"provider/model"`) or an object (`{ primary, fallbacks }`).
+  - Used by the `pdf` tool for model routing.
+  - If omitted, the PDF tool falls back to `imageModel`, then to best-effort provider defaults.
+- `pdfMaxBytesMb`: default PDF size limit for the `pdf` tool when `maxBytesMb` is not passed at call time.
+- `pdfMaxPages`: default maximum pages considered by extraction fallback mode in the `pdf` tool.
 - `model.primary`: format `provider/model` (e.g. `anthropic/claude-opus-4-6`). If you omit the provider, OpenClaw assumes `anthropic` (deprecated).
 - `models`: the configured model catalog and allowlist for `/model`. Each entry can include `alias` (shortcut) and `params` (provider-specific, for example `temperature`, `maxTokens`, `cacheRetention`, `context1m`).
 - `params` merge precedence (config): `agents.defaults.models["provider/model"].params` is the base, then `agents.list[].params` (matching agent id) overrides by key.