chore(5956): add documentation to sentry usage

[DDDDDanica]

Description

The test-metamask Sentry project receives significant traffic (284,823 events in 14 days), but there's no clear documentation on sentry setup and usage. This PR add some comprehensive documentation that developers can reference.

Changelog

CHANGELOG entry: null

Related issues

Fixes: https://github.com/MetaMask/MetaMask-planning/issues/5956

Manual testing steps

1. Go to this page...

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

---

Note

Adds comprehensive Sentry documentation and clarifies Sentry DSN usage in the example config.

• Documentation (Sentry):
  • Adds detailed sections in development/README.md covering overview, environments, environment determination, DSN selection logic, common Sentry queries, local development setup, and testing methods.
  • Enhances guidance for release publishing with Sentry (UI/CLI setup and source maps verification).
• Configuration:
  • Updates .metamaskrc.dist with a clear Sentry configuration block, distinguishing SENTRY_DSN (production) vs SENTRY_DSN_DEV (non-production), and retains example DSN for development.

^{Written by Cursor Bugbot for commit 4563265. This will update automatically on new commits. Configure here.}

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[metamaskbot]

Builds ready [4563265]

• builds: chrome, firefox
• builds (beta): chrome, firefox
• builds (flask): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• bundle size: Bundle Size Stats
• user-actions-benchmark: User Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18
  • content-script: 0
  • offscreen: 0

UI Startup Metrics (1252 ± 82 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Standard Home	uiStartup	1252	1051	1448	82	1315	1385
			load	1033	866	1241	71	1080	1140
			domContentLoaded	1026	863	1222	69	1075	1130
			domInteractive	21	16	38	6	22	37
			firstPaint	526	83	1250	411	1035	1131
			backgroundConnect	217	196	255	12	222	246
			firstReactRender	46	30	193	19	51	75
			getState	38	18	126	22	41	101
			initialActions	1	0	4	1	1	2
			loadScripts	816	663	1020	66	860	908
			setupStore	12	7	47	6	13	24
			numNetworkReqs	8	6	30	7	6	30
	Browserify	Power User Home	uiStartup	1880	1616	2411	137	1951	2085
			load	1084	874	1341	106	1169	1256
			domContentLoaded	1071	866	1290	104	1163	1234
			domInteractive	26	17	54	7	27	43
			firstPaint	548	92	1346	420	1066	1202
			backgroundConnect	245	203	578	76	237	528
			firstReactRender	44	35	96	7	46	54
			getState	197	147	332	35	214	271
			initialActions	1	0	2	1	1	2
			loadScripts	858	667	1087	102	954	1025
			setupStore	17	10	56	9	15	40
			numNetworkReqs	69	57	203	22	66	103
	Webpack	Standard Home	uiStartup	913	734	1229	88	963	1062
			load	697	589	943	79	745	853
			domContentLoaded	691	584	935	79	740	848
			domInteractive	24	16	58	8	25	44
			firstPaint	244	92	914	172	236	714
			backgroundConnect	13	6	52	10	14	37
			firstReactRender	68	37	336	52	72	175
			getState	26	13	55	10	31	47
			initialActions	1	0	3	1	1	2
			loadScripts	688	582	933	79	738	846
			setupStore	12	7	32	5	13	23
			numNetworkReqs	8	6	30	5	6	23
	Webpack	Power User Home	uiStartup	1495	1210	2127	158	1592	1770
			load	736	609	933	79	781	884
			domContentLoaded	728	603	925	77	772	873
			domInteractive	25	17	54	8	26	47
			firstPaint	314	93	936	237	259	859
			backgroundConnect	59	7	573	108	55	292
			firstReactRender	48	40	87	6	50	59
			getState	203	145	327	43	237	287
			initialActions	1	0	2	1	1	2
			loadScripts	725	601	922	77	766	869
			setupStore	14	10	40	6	14	34
			numNetworkReqs	67	22	202	17	66	98
Firefox	Browserify	Standard Home	uiStartup	1264	1091	1591	112	1345	1499
			load	1034	939	1253	69	1083	1174
			domContentLoaded	1034	932	1252	69	1083	1174
			domInteractive	53	31	137	26	74	110
			firstPaint	-	-	-	-	-	-
			backgroundConnect	37	20	141	23	36	97
			firstReactRender	36	30	64	8	36	57
			getState	11	5	206	20	10	21
			initialActions	1	0	2	0	2	2
			loadScripts	1013	923	1228	66	1057	1146
			setupStore	10	6	29	4	10	22
			numNetworkReqs	8	6	26	5	6	24
	Browserify	Power User Home	uiStartup	2571	1534	3444	600	3091	3330
			load	1507	947	2447	541	2104	2351
			domContentLoaded	1507	947	2447	541	2104	2351
			domInteractive	78	26	1064	141	69	132
			firstPaint	-	-	-	-	-	-
			backgroundConnect	140	21	1188	167	188	319
			firstReactRender	53	32	181	18	56	79
			getState	150	72	1044	102	174	236
			initialActions	2	0	4	1	2	3
			loadScripts	1435	932	2426	494	1995	2230
			setupStore	76	5	1130	174	60	379
			numNetworkReqs	69	44	121	13	71	97
	Webpack	Standard Home	uiStartup	1568	1319	2092	141	1659	1876
			load	1271	1122	1566	83	1319	1421
			domContentLoaded	1271	1122	1566	83	1318	1421
			domInteractive	63	28	230	40	82	140
			firstPaint	-	-	-	-	-	-
			backgroundConnect	46	22	186	26	49	106
			firstReactRender	42	34	57	6	43	54
			getState	21	8	203	30	17	94
			initialActions	1	0	2	1	2	2
			loadScripts	1246	1097	1542	82	1294	1388
			setupStore	13	6	134	15	12	29
			numNetworkReqs	8	6	26	6	8	25
	Webpack	Power User Home	uiStartup	2789	1813	4180	574	3215	3518
			load	1806	1117	2745	527	2320	2477
			domContentLoaded	1806	1116	2745	527	2320	2477
			domInteractive	148	29	1092	281	78	1039
			firstPaint	-	-	-	-	-	-
			backgroundConnect	152	24	1288	231	177	991
			firstReactRender	54	34	103	12	59	84
			getState	149	84	1155	111	176	237
			initialActions	2	1	3	1	2	3
			loadScripts	1707	1101	2591	487	2225	2425
			setupStore	61	4	1039	154	41	288
			numNetworkReqs	70	53	124	14	71	100

📊 Page Load Benchmark Results

Current Commit: 4563265 | Date: 12/8/2025

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

• pageLoadTime-> current mean value: 1.04s (±96ms) 🟡 | historical mean value: 1.05s ⬇️ (historical data)
• domContentLoaded-> current mean value: 729ms (±118ms) 🟢 | historical mean value: 730ms ⬇️ (historical data)
• firstContentfulPaint-> current mean value: 93ms (±186ms) 🟢 | historical mean value: 78ms ⬆️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.04s	96ms	1.00s	1.96s	1.06s	1.96s
domContentLoaded	729ms	118ms	697ms	1.88s	743ms	1.88s
firstPaint	93ms	186ms	56ms	1.94s	84ms	1.94s
firstContentfulPaint	93ms	186ms	56ms	1.94s	84ms	1.94s
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

Bundle size diffs [🚨 Warning! Bundle size has increased!]

• background: -911 Bytes (-0.02%)
• ui: 126.73 KiB (1.64%)
• common: 1.7 KiB (0.02%)