Coverage report display fails loading for large files (LOC > 800)

### Jenkins and plugins versions report

Environment

```text
Jenkins: 2.568.2
OS: Windows Server 2022 - 10.0
Java: 25.0.3 - Eclipse Adoptium (OpenJDK 64-Bit Server VM)
---
analysis-model-api:14.16.0-1014.v2802998b_7789
ansicolor:542.v03d235fee02d
ant:520.vd082ecfb_16a_9
antisamy-markup-formatter:173.v680e3a_b_69ff3
apache-httpcomponents-client-4-api:4.5.14-269.vfa_2321039a_83
apache-httpcomponents-client-5-api:5.6.4-204.vfa_29df89ffcf
asm-api:9.10.1-216.va_9256d3b_844b_
authentication-tokens:1.144.v5ff4a_5ec5c33
bootstrap5-api:5.3.8-1048.va_c299057e35c
bouncycastle-api:2.30.1.84-291.v9f17b_21896e2
branch-api:2.1280.v0d4e5b_b_460ef
build-timeout:1.41
caffeine-api:3.2.4-208.v7e2da_a_7db_82b_
calendar-view:0.5.3
checks-api:415.vf022234a_931d
cloudbees-bitbucket-branch-source:937.3.10
cloudbees-folder:6.1106.v3a_d9a_6d2465e
command-launcher:134.v025a_5fcf9dea_
commons-collections4-api:4.5.0-8.va_d5448ef9011
commons-lang3-api:3.20.0-109.ve43756e2d2b_4
commons-text-api:1.15.0-218.va_61573470393
coverage:3.3358.v9487dde48783
credentials:1511.v2e3cb_0008ef0
credentials-binding:728.v902a_273b_8947
cvs:502.v02d5a_0c6b_9a_3
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data-tables-api:2.3.8-1570.v1cb_1cd2a_0fb_c
datadog:9.2.0
display-url-api:2.217.va_6b_de84cc74b_
docker-commons:477.v289085a_b_6896
docker-workflow:653.v2f2c08eff0ec
durable-task:686.v80ff80875b_82
echarts-api:6.1.0-1306.vcee1648c16a_4
eddsa-api:0.3.0.1-29.v67e9a_1c969b_b_
email-ext:2038.v7b_8817a_499d9
embeddable-build-status:666.vcb_0de9eb_43d8
external-monitor-job:223.vb_fddcf42c9b_3
favorite:2.267.vb_90d08408081
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forensics-api:4.1923.v445c56df9b_2e
git:5.10.1
git-client:6.6.1
git-forensics:4.2463.vf6fecb_444a_b_3
git-server:137.ve0060b_432302
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htmlpublisher:429
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ionicons-api:94.vcc3065403257
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jackson2-api:2.22.2-445.vdc613f1d8012
jackson3-api:3.2.2-96.v599957900a_1a_
jakarta-activation-api:2.1.4-1
jakarta-mail-api:2.1.5-1
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javadoc:354.vee1a_660b_4990
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javax-mail-api:1.6.2-11
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job-restrictions:242.v6edda_c9e4ca_f
joda-time-api:2.14.3-200.v65623733c99f
jquery:1.12.4-3
jquery3-api:3.7.1-687.v68d468e40b_30
jsch:0.2.16-95.v3eecb_55fa_b_78
json-api:20260814-226.v20f9685d642c
json-path-api:3.0.0-218.vcd4dd1355de2
jsoup:1.23.1-103.v4fde9422cc6f
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ldap:807.809.vd3a_4e5e4ec98
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lockable-resources:1554.v491fcb_27c716
mailer:534.v1b_36f5864073
mapdb-api:1.0.9-44.va_1e1310c9118
matlab:1124.v8b_2e953b_6438
matrix-auth:3.3
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mercurial:1323.ve69d2a_db_8a_b_d
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mina-sshd-api-common:2.19.0-192.v2b_a_7b_2c1dc71
mina-sshd-api-core:2.19.0-192.v2b_a_7b_2c1dc71
monitoring:2.8.0
msbuild:1.43
okhttp-api:5.3.2-200.vedb_720a_cf1f8
oss-symbols-api:465.v25d9fdc88c26
pam-auth:1.12
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pipeline-github-lib:65.v203688e7727e
pipeline-graph-analysis:254.v0f63a_a_447dca_
pipeline-graph-view:998.vc30deece0e36
pipeline-groovy-lib:798.v5cc688825312
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pipeline-stage-view:2.41
plain-credentials:199.v9f8e1f741799
plugin-util-api:7.1341.v039f146993d9
prism-api:1.30.0-741.v034eb_0b_0a_a_fa_
pubsub-light:1.19
resource-disposer:0.25
saferestart:102.v4dc1b_9636a_ee
scm-api:728.vc30dcf7a_0df5
script-security:1412.v7737b_3405f86
snakeyaml-api:2.5-149.v72471e9c6371
snakeyaml-engine-api:3.1.1-12.v4320c7d6f89c
sse-gateway:1.29
ssh-credentials:372.va_250881b_08cd
ssh-slaves:3.1097.v868116049892
sshd:3.384.vc89b_5e138cf9
structs:362.va_b_695ef4fdf9
subversion:1303.vcfd9679fb_c12
theme-manager:346.v06cca_64c6a_37
thinBackup:2.1.5
timestamper:1.30
token-macro:477.vd4f0dc3cb_cf1
trilead-api:2.284.v1974ea_324382
variant:70.va_d9f17f859e0
versioncolumn:400.v3c5c3004f31d
warnings-ng:13.10223.v8f61dc07f2df
woodstox-core-api:7.2.2-10.vcb_629759b_2c2
workflow-aggregator:608.v67378e9d3db_1
workflow-api:1413.v2ff1a_5e720fa_
workflow-basic-steps:1098.v808b_fd7f8cf4
workflow-cps:4370.v49a_6937566b_6
workflow-durable-task-step:1479.v56e587f413a_7
workflow-job:1595.v0ee1a_de2c0a_3
workflow-multibranch:841.vec5b_9e1806ec
workflow-scm-step:466.va_d69e602552b_
workflow-step-api:724.v538c2362b_dfb_
workflow-support:1015.v785e5a_b_b_8b_22
ws-cleanup:0.49
```

### What Operating System are you using (both controller, and any agents involved in the problem)?

Windows Server 20202, on both agent and controller.

### Reproduction steps

When loading large files (LOC>800) in Coverage report, I get a message about the page getting unresponsive

### Expected Results

I'd expected the file to load without problems, even with large LOC.

Anyways this was the case for older versions of the Coverage plugin.

### Actual Results

Loading of the large file fails and page becomes unresponsive:

When I press 'Wait' the problem persists.

I also notice that when files getting larger, it takes mre time to load wehn scrolling.

### Anything else?

I am happy with the new layout of the Coverage page, with red/gren coloring in the left gutter.

### Are you interested in contributing a fix?

_No response_

Start by reproducing the problem in the Coverage report with a file over 800 lines and observe the page-rendering and scrolling behavior. No file or test is named, so locate the report rendering entry point before investigating; done means large files load and remain responsive without changing the reported coverage display.

Written by the indexing model from the issue text.