Distinguish between initial and resumed watch phases for streaming lists

[doxxx93]

Motivation

Fixes #1844

When using streaming_lists() mode, users observe duplicate events every ~290 seconds. This happens because watch connections timeout after 290s (Kubernetes API limitation), and when reconnecting, the watcher incorrectly sets sendInitialEvents=true, causing the API server to resend all objects.

The root cause is that to_watch_params() always sets send_initial_events=true for StreamingList mode, regardless of whether it's an initial watch or a reconnection.

Solution

Introduce a WatchPhase enum to distinguish between initial and resumed watches:

enum WatchPhase {
    Initial,  // from State::Empty - requests initial events
    Resumed,  // from State::InitListed - no initial events
}

• WatchPhase::Initial: Used when starting a fresh streaming list watch, sets sendInitialEvents=true
• WatchPhase::Resumed: Used when reconnecting after timeout, sets sendInitialEvents=false

This aligns with how client-go handles streaming lists - it uses watchList() for initial sync and watch() for reconnections, never requesting initial events on reconnection.

[codecov]

Codecov Report

❌ Patch coverage is 70.37037% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.1%. Comparing base (10efa00) to head (7357151).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
kube-runtime/src/watcher.rs	70.4%	8 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1882     +/-   ##
=======================================
+ Coverage   76.0%   76.1%   +0.2%     
=======================================
  Files         85      85             
  Lines       8267    8285     +18     
=======================================
+ Hits        6275    6301     +26     
+ Misses      1992    1984      -8     

Files with missing lines	Coverage Δ
kube-runtime/src/watcher.rs	48.6% <70.4%> (+4.8%)	⬆️

... and 5 files with indirect coverage changes

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[doxxx93]

I will add some tests

[clux]

Thanks a lot! This looks great to me. Did a quick sanity run and it does indeed fix the underlying problem.

[clux]

Happy to merge?

[doxxx93]

Yeah 😀