EMBR-12558 feat: roll over session part on soft navigation

[joaquin-diaz]

What problem is this solving?

SPA soft navigations (React Router link clicks, browser back/forward) were not triggering session part rollovers. The Navigation API's currententrychange event is the right hook but was unwired.

Short description of changes

• Wire _rolloverSessionPart to navigation.currententrychange via a new onSoftNavigation activity listener in activity.ts
• Add Navigation and SoftNavigationEvent interfaces in common/types.ts to type the Navigation API without casting; NavigationHost now types navigation as Navigation instead of EventTarget
• Add location: { href: string } to NavigationHost so the handler can detect same-URL replacements without accessing window.location directly
• Skip rollover when event.from.url === navigationHost.location.href to avoid spurious rollovers from framework hydration (e.g. Next.js App Router fires currententrychange via history.replaceState during hydration with the same URL)
• Add navigationHost?: NavigationHost to EmbraceUserSessionManagerArgs; defaults to window
• Add 5 unit tests covering: rollover on soft-nav, no-op when no active part, listener cleanup on shutdown, graceful handling of absent Navigation API, no-op on same-URL navigation
• Increase bundle size limit from 55 to 56 KB
• Restructure integration test ReceivedSpans from Record<string, boolean> to Record<string, Record<string, { endReason }>>, keyed by session part ID — enables server-side count validation
• Consolidate validateThatSessionPartEnded / validateThatSessionPartsEnded into a single validateThatSessionPartsEnded(expectedCount = 1, userSessionId?) that polls /received-spans for accuracy
• Remove test.skip from all three Vite React Router SPA navigation e2e tests

How has this been tested?

• Unit tests: all 27 tests in EmbraceSessionPartActivity.test.ts pass (22 existing + 5 new)
• Integration tests: SPA navigation e2e tests in vite-react-router-tests.spec.ts are unskipped and exercise forward links, browser back, and browser forward scenarios; Next.js integration tests all pass (same-URL skip fix prevents spurious rollovers during hydration)

Checklist

• Tests added
• Documentation added

[github-actions]

Chrome DevTools Protocol Tracing (Script: 120.63ms, Heap: 13.01MB)

	Number of Requests	Size of Requests	Script Duration	Task Duration	Heap Used Size
Requests	+4 requests	+33.74 KB
Page Loaded			+23.91 ms	+21.28 ms	+1.17 MB
Generate 100 fetch requests			+21.19 ms	+84.32 ms	+1.69 MB
Generate 100 XHR requests			+42.61 ms	+112.75 ms	+2.83 MB
Click 100 buttons and generate 100 logs			+23.38 ms	+43.50 ms	+2.14 MB
Throw a 100 exceptions			+0.03 ms	+24.16 ms	+3.21 MB
End Session			+9.51 ms	+25.27 ms	+1.96 MB
Total	+4 requests	+33.74 KB	+120.63 ms	+311.28 ms	+13.01 MB

Lighthouse (Script Eval: 123.86ms)

	Difference	Description
Total Blocking Time	+1 ms	Difference in Total Blocking Time: Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more about the Total Blocking Time metric.
Main Thread Time	+95.35 ms	Difference in Main Thread Time: Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work
Script Evaluation Time	+123.86 ms	Difference in Script Evaluation Time: Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Platform Tests (vite-7 es2015 gzip: 68.46KB)

vite-6 Platform Tests

	Total Uncompressed Size	Total Gzip Size
vite-6 - es2015	+198.80 KB	+68.50 KB

vite-7 Platform Tests

	Total Uncompressed Size	Total Gzip Size
vite-7 - es2015	+198.80 KB	+68.46 KB

webpack-5 Platform Tests

	Total Uncompressed Size	Total Gzip Size
webpack-5 - es2015	0 KB	0 KB

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.64%. Comparing base (e004016) to head (d3341b0).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1398      +/-   ##
==========================================
+ Coverage   96.41%   96.64%   +0.23%     
==========================================
  Files         230      230              
  Lines        9718     9759      +41     
  Branches     1353     1360       +7     
==========================================
+ Hits         9370     9432      +62     
+ Misses        346      325      -21     
  Partials        2        2              

Files with missing lines	Coverage Δ
packages/web-sdk/src/common/index.ts	100.00% <100.00%> (ø)
...aceUserSessionManager/EmbraceUserSessionManager.ts	95.08% <100.00%> (+2.09%)	⬆️
...nagers/EmbraceUserSessionManager/utils/activity.ts	100.00% <100.00%> (ø)

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[overbalance]

I recommend expanding the reason value. Otherwise looks great!

[jpmunz]

Won't we also need to ignore fragment and query string changes here?

[joaquin-diaz]

event.from.url and this._navigationHost.location.href include the entire query string so navigating to the same URL (including qs) would be ignored