fix(create): Add helpful error messages for hyphen-prefixed function names mis-parsed as flags

[RayyanSeliya]

Changes

• 🐛 Fix confusing errors when function names start with hyphens
• 🎁 Add DNS-1035 naming guidance for mis-parsed arguments
• ✨ Detect hyphen-prefixed names across multiple error paths

Adds detection and helpful error messages when function names starting with hyphens (e.g., -test-func, --production-func, -123) are mis-parsed as CLI flags. Users now receive clear guidance about DNS-1035 naming rules instead of confusing "template not found" or "unknown flag" errors.

Implementation:

• Add wrapFlagParsingError() and wrapFlagParsingErrorWithDetails() helper functions (cmd/errors.go)
• Add custom flag error handler in NewCreateCmd() to intercept Cobra flag parsing errors (cmd/create.go)
• Enhance newInvalidRuntimeError() and newInvalidTemplateError() to detect mis-parsed names (cmd/create.go)

Error Message Example:

Error: The template 'est-func' was not found for language runtime 'go'.
Available templates for this language runtime are:
  cloudevents
  http

Note: It looks like '-test-func' was interpreted as the flag '-t' with value 'est-func'.
Function names cannot start with hyphens per DNS-1035 naming rules.
Valid function names must start with a letter (a-z) and can contain letters, numbers, and hyphens.

/kind bug

Fixes #3166

Release Note

Function names starting with hyphens now show helpful DNS-1035 naming guidance instead of confusing flag parsing errors

[knative-prow]

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[knative-prow]

Hi @RayyanSeliya. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[codecov]

Codecov Report

❌ Patch coverage is 16.66667% with 40 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.98%. Comparing base (0bc91f3) to head (ce7c1ed).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/create.go	26.66%	19 Missing and 3 partials ⚠️
cmd/errors.go	0.00%	18 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3167      +/-   ##
==========================================
+ Coverage   59.39%   59.98%   +0.59%     
==========================================
  Files         134      134              
  Lines       13514    13560      +46     
==========================================
+ Hits         8026     8134     +108     
+ Misses       4547     4453      -94     
- Partials      941      973      +32     

Flag	Coverage Δ
e2e-tests	41.49% <0.00%> (+1.31%)	⬆️
integration-tests	54.56% <16.66%> (+1.53%)	⬆️
unit-tests	46.61% <16.66%> (-0.13%)	⬇️

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[RayyanSeliya]

hey @gauron99 can have a look and point me if any tweaks needed !

[RayyanSeliya]

/ok-to-test