feat(pyamber): hash epoch timestamps on Windows

[carloea2]

What changes were proposed in this PR?

Attach the system local timezone before converting naive timestamps for tuple hashing. This avoids the Windows pre-epoch failure while preserving aware timestamps and Java-compatible epoch seconds.

Any related issues, documentation, discussions?

Closes #8211

How was this PR tested?

python -c "import sys,pytest; sys.path[:0]=[r'<worktree>ambersrcmainpython',r'<main-checkout>ambersrcmainpython']; raise SystemExit(pytest.main([r'amber/src/test/python/core/models/test_tuple.py::TestTuple::test_hash_supports_local_epoch_timestamp','-q','-p','no:cacheprovider']))"
1 passed

python -c "import sys,pytest; sys.path[:0]=[r'<worktree>ambersrcmainpython',r'<main-checkout>ambersrcmainpython']; raise SystemExit(pytest.main([r'amber/src/test/python/core/models/test_tuple.py','-q','-p','no:cacheprovider','-k','not test_hash']))"
101 passed, 3 deselected

ruff check amber/src/main/python amber/src/test/python
All checks passed

ruff format --check amber/src/main/python amber/src/test/python
213 files already formatted

The broader existing test_hash now passes its epoch assertion but later fails while its Windows fixture calls datetime.fromtimestamp with a negative value, before Texera hashing runs.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Codex

[github-actions]

Backport auto-label report

This fix: PR was checked against each actively-supported release branch. release/* labels drive the post-merge backport, so add or remove one to change where this fix lands.

Release branch	Analysis
⚠️ release/v1.3	Not labeled automatically — none of the files this PR modifies exist on this branch (amber/src/main/python/core/models/tuple.py, amber/src/test/python/core/models/test_tuple.py). The fix may target code that isn't on this release, or the files were moved/renamed after the branch was cut. Please check and add release/v1.3 by hand if this fix should be backported here.
✅ release/v1.2	Change detected on this branch — label added; this fix is queued to backport here. Requested review from @xuang7.

Auto-label run.

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @eugenegujing, @aglinxinyuan
  You can notify them by mentioning @eugenegujing, @aglinxinyuan in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.94%. Comparing base (70c2114) to head (2129adf).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8212   +/-   ##
=========================================
  Coverage     93.94%   93.94%           
  Complexity     4759     4759           
=========================================
  Files          1185     1185           
  Lines         48069    48070    +1     
  Branches       5359     5359           
=========================================
+ Hits          45159    45160    +1     
  Misses         1480     1480           
  Partials       1430     1430           

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 70c2114
agent-service	99.32% <ø> (ø)		Carriedforward from 70c2114
amber	89.99% <ø> (ø)		Carriedforward from 70c2114
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 70c2114
config-service	86.86% <ø> (ø)		Carriedforward from 70c2114
file-service	87.91% <ø> (ø)		Carriedforward from 70c2114
frontend	96.49% <ø> (ø)		Carriedforward from 70c2114
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 70c2114
pyamber	98.87% <100.00%> (+<0.01%)	⬆️
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 70c2114

*This pull request uses carry forward flags. Click here to find out more.

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[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 5 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main 70c2114 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	430	0.262	23,146/29,737/29,737 us	🔴 +9.1% / 🔴 +90.9%
🔴	bs=100 sw=10 sl=64	920	0.561	107,112/148,528/148,528 us	🔴 +10.4% / 🔴 +38.5%
⚪	bs=1000 sw=10 sl=64	1,092	0.667	911,018/998,858/998,858 us	⚪ within ±5% / 🟢 -7.2%

Baseline details

Latest main 70c2114 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	430 tuples/sec	461 tuples/sec	787.98 tuples/sec	-6.7%	-45.4%
bs=10 sw=10 sl=64	MB/s	0.262 MB/s	0.281 MB/s	0.481 MB/s	-6.8%	-45.5%
bs=10 sw=10 sl=64	p50	23,146 us	21,212 us	12,593 us	+9.1%	+83.8%
bs=10 sw=10 sl=64	p95	29,737 us	32,632 us	15,579 us	-8.9%	+90.9%
bs=10 sw=10 sl=64	p99	29,737 us	32,632 us	18,786 us	-8.9%	+58.3%
bs=100 sw=10 sl=64	throughput	920 tuples/sec	949 tuples/sec	1,008 tuples/sec	-3.1%	-8.7%
bs=100 sw=10 sl=64	MB/s	0.561 MB/s	0.579 MB/s	0.615 MB/s	-3.1%	-8.8%
bs=100 sw=10 sl=64	p50	107,112 us	103,694 us	100,701 us	+3.3%	+6.4%
bs=100 sw=10 sl=64	p95	148,528 us	134,479 us	107,244 us	+10.4%	+38.5%
bs=100 sw=10 sl=64	p99	148,528 us	134,479 us	116,122 us	+10.4%	+27.9%
bs=1000 sw=10 sl=64	throughput	1,092 tuples/sec	1,086 tuples/sec	1,042 tuples/sec	+0.6%	+4.8%
bs=1000 sw=10 sl=64	MB/s	0.667 MB/s	0.663 MB/s	0.636 MB/s	+0.6%	+4.9%
bs=1000 sw=10 sl=64	p50	911,018 us	928,345 us	981,959 us	-1.9%	-7.2%
bs=1000 sw=10 sl=64	p95	998,858 us	998,661 us	1,023,080 us	+0.0%	-2.4%
bs=1000 sw=10 sl=64	p99	998,858 us	998,661 us	1,051,697 us	+0.0%	-5.0%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,465.12,200,128000,430,0.262,23145.78,29736.74,29736.74
1,100,10,64,20,2174.46,2000,1280000,920,0.561,107112.28,148527.94,148527.94
2,1000,10,64,20,18308.72,20000,12800000,1092,0.667,911017.53,998857.61,998857.61