feat(tree): getOrInsert and getOrInsertComputed mapNode alpha API

[brrichards]

Description

Adds getOrInsert and getOrInsertedComputed alpha APIs for mapNode

Reviewer Guidance

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[Copilot]

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

[github-actions]

Hi! Thank you for opening this PR. Want me to review it?

Based on the diff (217 lines, 5 files), I've queued these reviewers:

• Correctness — logic errors, race conditions, lifecycle issues
• Security — vulnerabilities, secret exposure, injection
• API Compatibility — breaking changes, release tags, type design
• Performance — algorithmic regressions, memory leaks
• Testing — coverage gaps, hollow tests

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[Joshua Smithrud (Josmithr)]

Left a couple of docs suggestions. But overall they look great! Thanks for being so thorough!

[Daniel Madrid (dannimad)]

wait for #27824 to merge

[Joshua Smithrud (Josmithr)]

Docs and API changes look good. I'll let Craig and/or Yann approve the code changes though, since they've been more involved on that side of things.

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-website@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-website@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  309092 links
    1963 destination URLs
    2219 URLs ignored
       0 warnings
       0 errors

[github-actions]

Bundle size comparison

Base commit: d34c9cee41f6b5fcb9d157acbe53afda9402e036
Head commit: 0a41cabc1ec61b6065c01e65ff9d0b23a5bc1dc8

Notable changes

No bundles changed by ≥ 500 bytes parsed.

Per-bundle deltas

@fluid-example/bundle-size-tests

• azureClient.js: parsed 620351 → 620407 (+56), gzip 165482 → 165526 (+44)
• odspClient.js: parsed 592639 → 592695 (+56), gzip 158607 → 158652 (+45)
• aqueduct.js: parsed 526970 → 527005 (+35), gzip 141035 → 141063 (+28)
• fluidFramework.js: parsed 398233 → 398254 (+21), gzip 113049 → 113065 (+16)
• sharedTree.js: parsed 387637 → 387651 (+14), gzip 110478 → 110486 (+8)
• containerRuntime.js: parsed 305091 → 305105 (+14), gzip 83553 → 83558 (+5)
• sharedString.js: parsed 176457 → 176464 (+7), gzip 49807 → 49815 (+8)
• experimentalSharedTree.js: parsed 160677 → 160677 (0), gzip 46276 → 46276 (0)
• matrix.js: parsed 160302 → 160309 (+7), gzip 45800 → 45807 (+7)
• loader.js: parsed 145459 → 145473 (+14), gzip 39221 → 39235 (+14)
• odspDriver.js: parsed 103906 → 103927 (+21), gzip 32404 → 32411 (+7)
• directory.js: parsed 67110 → 67117 (+7), gzip 18859 → 18866 (+7)
• 578.js: parsed 58686 → 58686 (0), gzip 17657 → 17657 (0)
• map.js: parsed 47205 → 47212 (+7), gzip 14455 → 14462 (+7)
• odspPrefetchSnapshot.js: parsed 45635 → 45649 (+14), gzip 15242 → 15249 (+7)
• 252.js: parsed 44371 → 44371 (0), gzip 13732 → 13732 (0)
• summarizerDelayLoadedModule.js: parsed 30717 → 30717 (0), gzip 7716 → 7716 (0)
• socketModule.js: parsed 26469 → 26476 (+7), gzip 7896 → 7903 (+7)
• createNewModule.js: parsed 12454 → 12454 (0), gzip 4797 → 4797 (0)
• summaryModule.js: parsed 3789 → 3789 (0), gzip 1857 → 1857 (0)
• connectionState.js: parsed 909 → 909 (0), gzip 500 → 500 (0)
• sharedTreeAttributes.js: parsed 847 → 854 (+7), gzip 499 → 508 (+9)
• debugAssert.js: parsed 429 → 429 (0), gzip 299 → 299 (0)
• FluidFramework-HashFallback.js: parsed 419 → 419 (0), gzip 313 → 313 (0)