feat(mcp): catalog read tools

[andypalmi]

Summary

Read tools for the platform catalogs, added to forge/ee/lib/mcp/tools/platform.js. Adds get-by-id lookups (the list variants already exist) and the team-type catalog reads:

• platform_get_hosted_instance_type - GET /project-types/:instanceTypeId
• platform_get_stack - GET /stacks/:stackId
• platform_get_template - GET /templates/:templateId
• platform_get_blueprint - GET /flow-blueprints/:flowBlueprintId
• platform_list_team_types - GET /team-types
• platform_get_team_type - GET /team-types/:teamTypeId

Team types are a global platform catalog with no team in the path, mirroring project-types, so they are filed with the platform catalog tools following the one-file-per-resource convention. All tools are readOnlyHint: true, destructiveHint: false.

Scopes allow-listed for user:expert-mcp in forge/routes/auth/permissions.js:

• stack:read
• template:read
• flow-blueprint:read
• team-type:list
• team-type:read

(project-type:read was already allow-listed.)

Closes #7679

Test plan

• eslint on changed files passes
• CI

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.61%. Comparing base (103f9ae) to head (0bc2dce).

Additional details and impacted files

@@                        Coverage Diff                        @@
##           feat/mcp-tools-shared-schemas    #7721      +/-   ##
=================================================================
+ Coverage                          75.41%   75.61%   +0.19%     
=================================================================
  Files                                426      426              
  Lines                              22551    22576      +25     
  Branches                            5949     5949              
=================================================================
+ Hits                               17006    17070      +64     
+ Misses                              5545     5506      -39     

Flag	Coverage Δ
backend	75.61% <100.00%> (+0.19%)	⬆️

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